Vibrator



H. PRELL.

VIBRATOR.

APPLICATION FILED MAY 20, I918. 1,352,21 9. PatentedSept. 7, 1920.

7 I 27 g0 28 2e 1 1g. 1 8a E9 4 5 9 a nu H MI 9 g 5 4 o 11 85 5 E 52 I In \i UNITED STATES" HENRY PRELL, OF CLEVELAND, OHIO.

VIBRATOR.

Specification of Letters Patent.

Patented Sept. '7, 1920.

Application filed May 20, 1918. Serial No. 235,468.

To all whomz't may concern:

Be it known that I, HENRY PRELL, citizen of the United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Vibrators, of which the following is a specification.

This invention relates to vibrators such as are used for vibrating or jigging flasks or match plates in the preparation of molds for use in foundry operations.

The object of the invention is to provide an improved electrical vibrator capable of connection to an ordinary lamp socket, and which vibrator is of simple construction, is strong, durable, and not likely to get out of order, which may be applied to any flask or molding device, and which is so constructed as to avoid the heating effect of hysteresis.

Further objects of the invention are in part obvious and in part will appear morein detail hereinafter.

The invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the drawings, Figure 1 represents a sectional elevation, on the line 1-1, Fig. 2, through one form of vibrator embodying the invention; Fig. 2 is a plan View; Fig. 3 is a side elevation; Fig. 4 is an'end view, partly broken out and in section; Figs. 5 and 6 are detail views of a plug; and Fig. 7 is a plan view of the armature.

The vibrator shown in the drawings comprises a suitable outer casing or acket which incloses and protects the mechanism and which may also play its part in the production of the electromagnetic effect. The casing illustrated comprises a body member 1 which is substantially circular in plan view,

' as shown in Fig. 2, and which is hollowed out to provide a central core 2 surrounded by an annular chamber or recess 3, beyond which is a peripheral flange 4 having a lower annularly extending plane face 5 serving as an abutment for a purpose which will appear. Within the chamber 3 is a suitable solenoid coil 6 of insulated wire preferably wrapped or coated as an entirety to prevent short circuits to the casing. Said coil may also be wound at intervals with one or several layers of tape 7 to space it on all sides I from the casing and core 2. The lead wires from said coil extend outwardly through openings in an insulating plug 8 lying in an opening 9 in the casing, said plug on its outer end being provided with two opposite plug. The cord passes out from the casing through an outlet member 13 secured to a flat face on one side of the casing by screws 14? In the hollow bore of said member is a shoulder 15, serving as a means for holding in said member one end of a guard for the lamp cord, shown as a spiral spring 16 having one or more of its convolutions bent laterally into engagement with said shoulder 15. The outer end of member 13 has its surface 17 curved in radial cross section, as shown in Fig. 1, in order to protect the guard spring 16. This curved surface does away with sharp angles and causes the guard to bend uniformly when twisted or turned to one side or the other, so that the separate coils are not liable to become kinked, twisted or bent in use of the vibrator or in carrying it from place to place.

18 indicates an armature for cooperation with the solenoid coil 6. This armature is a comparatively heavy metal disk lying in axial alinement with the coil 6 and opposite the core 2. The diameter of said disk is larger than the outer diameter of the recess 3, as a consequence of which the outer portion of the disk overlaps the plane surface 5 of the casing. Armature 18 is supported upon the shank 19 of a bolt which passes through an opening in said armature and is threaded into an axial opening 20 of the core, the armature being prevented from escaping from the bolt by its head 21. Furthermore, adjustment of said bolt in its threaded opening in the core enables the armature to be adjusted toward and from the abutment surface 5, so as to vary its amount of movement. Said armature is normally held away from the coil and core by one ably machined ofl' slightly below the level of the abutment surface 5, or the armature can be recessed, as at 25*, as a consequence of which when the armature engages said abutment surface there is still a slight air gap between said armature and the core 2,

and any residual magnetism in said core will not cause the armature to stick to the core when the current is zero.

The vibrator is also preferably arranged for attachment or connection to the mold, flask, match plate, or'molding table or device which it is desired to vibrate. For example, the bolt 19 may have its shank suficiently long to enable it to be passed through a portion of the flask or table, to which it is secured by a nut screwed on the projecting end of the bolt. Under some circumstances the casing may be provided with a heavy solid lug or projection 26 having an opening 27, through which a bolt can be passed to secure the casing to the mold, flask or table. iVith this latter arrangement a nut 28 is screwed on the end of the bolt 19 to lock said bolt in adjusted position.

The vibrator is used with alternating current, say 60 cycle, the efl'ect being to energize the coil and core to a maximum during each half of the alternating wave. In other words, two impulses of current pass through the coil for each cycle, and at each impulse the coil and core are energized and cause the armature to strike the abutment surface 5 and impart a blow or shock to the mold, flask or table to which the vibrator is secured or upon which it rests. As the alternating current wave crosses the zero line the electromagnetic effect also becomes practically Zero and the armature is retracted or returned to initial position by its springs 22, thereby engaging the bolt head 21 and causing another blow or jar.

lln devices of this kind sustained current through the coil causes hysteresis with the production of the usual heating results. In order to avoid this and other hysteresis eflects the continuity of the casing, core and armature is broken and the materials of which said parts are made are chosen with due regard to hysteresis. As illustrated the armature 18 is broken up by slotting the same radially from its center to one side, as indicated at 29. This slot may be an ordinary saw cut. llt breaks up. the annular continuity of the armature. The casing body 1 is also provided with a similar radially extending slot or slots 30, one of which is substantially opposite to the reinforcing lug or car 26, and which preferably also passes diametrically through the inner core 2, as shown in dotted lines, Fig. 2. These slots 29 and 30 do not materially weaken the casing or armature and are found to largely avoid any heating eifect. At the same time the casing body and armature are made of semi-steel, a material which is not so crystalline as cast metal and which therefore does not wear off rapidly, and which is also easier to cast and finish than true steel and- -will stand up well under the impact of vibration. The bolt is made of a suitable strong tough chrome vanadian steel. Its head is comparatively shallow, so that said bolt does not collect and hold heat, but radiates it rapidly to other parts.

The casing includes not only body 1 but also a cover or cap 31 which is preferably a hollow member made of insulating material, such as maple or other fine grained wood, said cap being secured-to the body by screws 32 passing through openings in the flange 4: into the flange of the cap. This 'cap incloses and protects the armature and coil from injury. Insulating material is necessary for the cap to avoid making the casing in effect annularly continuous.

The vibrator described is of simple construction and produces very efficient results in the vibration of parts to which it is secured or upon which it is supported.

l/Vhat I claim is:

1. A vibrator for use in the preparation of foundry molds, comprising a hollow casing adapted for attachment to the part to be vibrated and provided with an integral central core and an annular cavity surrounding the same, a coil in said cavity, a bolt adjustably threaded into ,said core and provided with a head forming a stationary abutment, and an armature slidable on said bolt and vibrating between said casing and bolt head. 2. A vibrator for use in the preparation of foundry molds, comprising a hollow casing adapted for attachment to the part to be vibrated and provided with an integral central core and an annular cavity surrounding the same, a coil in said cavity, a'bolt adjustably threaded into said core and provided with a head forming a stationary abutment, a circular armature slidable on said bolt and covering said cavity and vibrating between the casing and bolt head, and a series of yielding members spaced around the circumference of the casing radially outwardly beyond said cavity and engaging said armature for retracting the same from the coil.

. 3. A vibrator for use in the preparation of foundry molds, comprising a hollow. casing adapted for attachment to the part to be vibrated and provided with an integral central core and an annular cavity surrounding the same, a coil in said cavity, a bolt adjustably threaded into said core and provided with a head forming a stationary abutment, and an armature slidable on said bolt and vibrating between said casing and bolt head, said casing and core being slotted radially from the center outwardly to avoid hysteresis efi'ect.

4. A vibrator for use in the preparation of foundry molds, comprising a hollow casing adapted for attachment to the part to be vibrated and provided with an integralcentral core and an annular cavity surrounding the same, a coil in said cavity, a bolt adjustably threaded into said core and provided with a head forming a stationary abutment, acircular armature slidable on said bolt and covering said cavity and vibrating between the casing and bolt head, and a series of yielding members spaced around the circumference of the casing radially outwardly beyond said cavity and engaging said armature for retracting the same from the coil, said casing, core and armature being radially slotted from the center outwardly to avoid hysteresis effect.

5. A vibrator for use in the preparation of foundry molds, comprising a hollow casing adapted for attachment to the part to be vibrated and provided with an integral central core and an annular cavity surrounding the same, a coil in said cavity, a bolt adjustably threaded into said core and provided with a head forming a 'stationary abutment, and an armature slidable on said bolt and vibrating between said casing and bolt head, said armature having a series of through openings parallel to its line of movement to decrease air resistance.

6. A vibrator for use in the preparation of foundry molds, comprising a hollow casing adapted for attachment to the part to be vibrated and provided with an integral central core and an annular cavity surrounding the same, a coil in said cavity, a bolt adjustably threaded into said core and provided with a head forming a stationary abutment, a circular armature slidable on said bolt and covering said cavity and vibrating between the casing and bolt head, and a series of yielding members spaced around the circumference of the casing radially outwardly be yond said cavity and engaging said armature for retracting the same from the coil, said armature having a series of through openings parallel to its line of movement to decrease air resistance.

7. A vibrator for use in the preparation of foundry molds, comprising a hollow casing adapted for attachment to the part to be vibrated and provided with an integral central core and an annular cavity surrounding the same, a coil in said cavity, a bolt adjustably threaded into said core and provided with a head forming a stationary abutment, an armature slidable on said bolt and vibrating between said casing and bolt head, and a cap formed of non-magnetic material attached to said casing and inclosing said armature.

8. A vibrator for use in the preparation of foundrymolds, comprising a hollow casing adapted for attachment to the part to be vibrated and provided with an integral central core and an annular cavity surrounding the same, a coil in said cavity, a bolt adjustably threaded into said core and provided with a head forming a stationary abutment, a circular armature slidable on said bolt and covering said cavity and vibrating between the casing and bolt head, a series of yielding members spaced around the circumference of the casing radially outwardly beyond said cavity and engaging said armature for retracting the same from the coil, and a cap formed of non-magnetic material attached to said casing and inclosing said armature.

In testimony whereof I affix my signature.

HENRY PRELL. 

